The present invention relates to a method of reeling and unreeling reinforced veneer sheets. It is known to form elongated cuts in veneer sheets across the veneer grain and bury a cord or a string in the cuts for thereby preparing a train of interconnected veneer sheets. This process for providing cord-embedded veneer sheets is usable for various purposes such as reinforcing veneer sheets having cracks, joining veneer sheets containing defective portions, and joining neat veneer sheets which have the defective portions trimmed off. The present invention contemplates to provide an effective veneer sheet reeling and unreeling method by bringing such a reinforcing or joining process into cooperative relation with a process for winding the cord-embedded veneer sheets on a reel and a process for unwinding the same off the reel, thereby contributing a great deal to veneer processing in a plywood production line.
Typical proposals have heretofore been made concerning the cord burying process as disclosed in Japanese Pat. Nos. 33-6498, 49-32052 and 54-3926 as well as in our Japanese Patent Application Nos. 53-132252 and 53-137098. In any of these proposals, the strength to be provided to veneer sheets is basically determined by the strength with which a cord engages in the cuts of the veneer sheets. Another known type of process employs a adhesive in combination with a cord. A problem involved in this combined process is that, because a substantial period of time is necessary for the adhesive to produce an expected degree of strength, the adhesive in many cases fails to harden in time for a reeling operation which will follow the cord burying process. Then a veneer sheet is apt to be wound on a reel at a time when it is too early for the bonding strength of the adhesive to develop in addition to the veneer strength resulted from the cord. In any case, veneer sheets joined together with the aid of a cord and/or an adhesive tend to become disjoined by a load which will act on the veneer sheets during reeling operation. This frequently occurs also in the course of unreeling operation. Thus, the prior art methods cannot make the most of the reinforcing effect obtainable by burying a cord in veneer sheets. This is attributable to the fact that a cord slips out of the cuts of veneer sheets very easily when subjected to a load during reeling or unreeling. In other words, the cord burying, veneer reeling and unreeling steps are performed in the prior art without taking their inherent characteristics into consideration.